Attachment for furnaces and the like



April 20, 1943. F. A. SMITH ATTACHMENT FOR FURNACES AND THE LIKE Filed June 24, 1941 2 Sheets-Sheet l Im'enmr Z76 aler//r v7 SW/ii April 20, 1943. F. A. SMITH 2,317,229

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Patented Apr. 20, 1943 NT OFFICE ATTACHMENT FOR FURNACES AND THE LIKE Frederick A. Smith, Indianapolis, Ind.

Application June 24, 1941', Serial No. 399,542

1 Claim.

This invention has reference. to means for eliminating smoke and soot and consequently the saving of fuel; and is in the form of an attachment for hot-air furnaces, steam boilers/and the like, for the purpose stated.

In accordance with the present invention, the steam boiler, hot-air furnace or the like is equipped with means for returning the smoke and products of combustion to the fire chamber to be consumed thereby eliminating smoke and soot, and at the same time assuring maximum heat with minimum fuel consumption.

The invention together with its objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawings wherein:

Figure l is a view mostly in vertical section through a furnace, and illustrating the application of the invention thereto.

Figure 2 is a horizontal sectional view taken v substantially on the line 22 of Figure 1 and looking upwardly in the direction indicated by the arrows.

Figure 3 is a sectional view through the conduit forming part of the invention.

Figure 4 is an elevational view of a control switch forming part of the invention.

Referring more in detail to the drawings it will be seen that 5 indicates generally a conventional domestic heater in the form of a furnace,

and provided, as is conventional, with the outer casing 6, grate I, ash door 8, and, in the present instance, a thermostatic control indicated generally by the reference numeral 9.

In accordance with the present invention there is provided in the casing 5, preferably at the back of the casing, through the medium of a partition ID, a space H in which is positioned a conduit pipe [2.

The pipe |2 adjacent its upper end is provided with a lateral inlet neck I3 that has its free end fitted within an opening M provided therefor in the partition |U adjacent the upper end of the partition.

At the lower end thereof the pipe |2 merges into a lateral, horizontal extension l5 that extends into the ash pit of the furnace through an opening |6 provided therefor in the partition ll].

At its free end the extension I5 terminates in a vertical, upwardly directed, discharge neck that is positioned below the grate and terminates slightly below the grate as shown.

At the junction of the pipe extremity l5 and the neck said extremity I5 is provided at the bottom thereof, and in alignment with the neck Lil 11, with an opening |8 through which ashes and the. like falling from the fire-bed into the neck will pass into the ash pit and therefore not clog the pipe extension l5 or otherwise interfere with the return of the smoke and other products of combustion, as contemplated by the present invention.

At its upper extremity the pipe I2 is open, and at the junction between the pipe l2 and its lateral extension |5 said pipe |2 is provided in the periphery thereof with an opening through which a fan shaft l9 extends into the pipe I2,

On the inner end thereof the shaft l9 is provided with a fan 20, while at the opposite end thereof the shaft I9 is suitably connected with the armature shaft of an electric motor 2|.

For supporting the motor 2| there is provided a stand 22 exteriorly of the furnace casing 6.

The pedestal for the motor 2| may be bolted or otherwise secured to the stand 22.

Also mounted on the stand 22 is an electric switch 23 that is connected by suitable wiring 24 to the motor 2|, and by suitable wiring 25 to a source of current.

For controlling the operation of the switch 23 in response to the action of the thermostat 9, there is provided an operating link 26 that at one end has a pivotal connection 21 with the movable blade of the switch 23.

At the opposite end thereof the link 26 has a pin and slot or lost motion connection 28 with an arm 29 that intermediate its ends is operatively connected with the thermostat 9 exteriorly of the furnace casing. At the free end thereof the arm 29 is provided with a counterbalance 30.

The operation of the device is believed to be self-evident, but may be briefly described as follows:

The fan 20 driven from the electric motor 2| normally acts as a blower controlled by the thermostat 9 so that as the fire in the furnace dies down and the temperature is reduced, the thermostat 9 goes into operation for closing the switch 23 thus completing the circuit to the motor 2| for driving the fan 20. The fan 20 will serve to draw air from the atmosphere into the pipe |2 at the open end of the pipe and to force said air through the outlet neck I! to impinge against the fire-bed on the grate I thus promoting a draft for quickly creating a hot fire.

It will also be apparent that with the fan 20 in operation, smoke and products of combustion will be drawn from the space above the fire-bed through the inlet neck l3 of the pipe |2 and forced through the extension |5 to discharge therefrom at the outlet neck IT, with the result that such smoke and products of combustion will be further consumed.

From the foregoing, then, it will be seen that the device will operate substantially automatically to provide for the consumption of the smoke, soot, and other products of combustion to the end that objectionable accumulations of soot throughout the building will be eliminated, while at the same time the furnace will function more efficiently resulting in the obtaining of maximum heat from the furnace with minimum fuel consumption.

It will also be understood that while I have herein illustrated and described what is considered the preferred embodiment of the invention, and the preferred application thereof, I am well aware that the invention may be applied in other forms to other types of heaters to advantage, and therefore do not wish to limit myself to the precise application herein illustrated and described, or to the precise details of construction since in practical fields the details of construction may necessitate alterations falling within the scope of What is claimed.

Having thus described the invention what is claimed as new is:

The combination with a furnace having a grate, a combustion chamber above the grate, an ash pit below said grate, and a jacket forming an air space at the back of the chamber and pit, of an L-shaped conduit having a leg vertically disposed in said space and open at its top to take air therein from said space, a right angled leg extending through the back of said ash pit and provided with an upstanding end located directly beneath the center of the ash pit for discharging air through said grate into said chamber, said right angled leg having a discharge aperture in its bottom in line with the upstanding end for permitting ashes falling from said grate into said end to fall into the ash pit, a neck adjacent the top of said vertical leg extending through the back of the combustion chamber and opening into the top of the latter to draw smoke and other products of combustion out of said chamber, and a motor operated fan in said conduit at the juncture of said legs for creating a down draft in the Vertical leg and. a forced draft through the right angled leg.

FREDERICK A. SMITH. 

